Copying machine



y 9, 1967 D. F. ANDERSON Q 3,318,219

COPYING MACHINE Filed May 25, 1964 United States Patent 3,318,219 COPYING MACHINE Donald F. Anderson, St. Anthony Village, Minn., assignor to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware Filed May 25, 1964, Ser. No. 369,893 9 Claims. (Cl. 95-73) This invention relates to the copying of printed matter and the like, and has particular reference to copying machines useful in the copying of graphic originals in accord ance with principles set forth in Workman US. Patent No. 3,094,417.

The Workman patent describes the copying of printed matter by a process involving exposure to light followed by treatment with heat. As illustrated particularly in Example 3 of that patent, a light-sensitive sheet is first completely desensitized at background areas by exposure in reflex position, i.e. by light passing through the sheet to the printed original held in contact therewith. The sheet is only partially desensitized at areas corresponding to the radiation-absorptive image areas of the original. Heating the thus exposed sheet in face-to-face contact with a suitably coated copy-sheet then produces on the latter a visible reproduction of the image areas by inter-reaction between the residual sensitizing component of the exposed sheet and the reactant-containing surface of the copy-sheet.

The copying machine of the present invention is useful in making copies from books and magazines as well as from printed correspondnece, sketches or drawings. It is particularly useful in the preparation of multiple copies of single-sheet multi-color graphic originals by a completely automatic process involving merely inserting the original and copy-paper, setting a counter for the desired number of copies, and initiating the copy sequence.

In the drawings,

FIGURE 1 is a view in chine of the invention, I

FIGURE 2 is a schematic sectional view illustrating the relationship of the major components,

FIGURE 3 is a schematic illustration in perspective showing the linkages employed in operating the pressure member of the exposure system,

FIGURE 4 is a partial end elevation taken from the right end of the machine as seen in FIGURE 2, and

FIGURE 5 is a partial plan view showing additional detail of the copy-sheet feed mechanism.

The machine of FIGURE 1 is contained within a casing 11 having a print entry port 12, a copy-paper entry port 13, a control panel 14, and a pressure platen 15. A control handle 16 extends from a side of the platen 15, and a paper feed initiator handle 17 is located near the entry port 13. A tray 18 for supporting a stack of copy-paper lies within the port 13. A slanting feed plate 19 in a port 12 serves to direct the printed graphic original into the machine.

The operation of the machine is conveniently followed by reference to FIGURE 2. A light-desensitizable intermediate sheet material 20 in continuous strip form is unwound from supply roll 21, directed around guide roll 22 and between metering feed roll 23 and pressure roll 24, and thence across the glass top 25 of exposure chamber 26. A suitable graphic original 27 which is to be copied is inserted at feed plate 19 and is advanced by entry roll 28 to the nip between rolls 23 and 24 and into contact with the strip 20, where it is dynamically held in registry. The feed roll 23 then advances the strip 20 and original 27 together and into position for reflex exposure from the chamber 26, the strip 20 being drawn taut over guide rolls 29, 30 and 31 by tension applied at windup roll 32.

perspective of a copying ma- 3 ,318,219 Patented May 9, 1967 ICC With the printed original in position for exposure, the pressure platen 15 is lowered, by cam means here indicated by cam 33, to place the original and intermediate into close uniform contact with each other on the glass plate 25. The lamps 34 are then turned on for a time interval just sufiicient to cause complete desensitization of the sensitive strip 20 at areas corresponding to the unprinted background areas of the original. The platen 15 is then raised to the open position.

The feed roll 23 and windup roll 32 next advance the intermediate to an extent sufficient to position the exposed portion directly beneath the curved heater platen 35. During this operation the original is detached from the intermediate and delivered to a recovery chute 50.

In the meantime a copy-sheet 36 has been fed from the stack of sheets 37 supported on tray 18 into position on the curved pressure table 38, by the action of the feed roll 39, control bar 40, guide panel 41, pressure fingers 42, feed roll 43, and pressure roll 44. The table 38 is raised by cam 45 operating against equalizing pad 46, pressing the copy-sheet 36 into close uniform contact with the exposed portion of the intermediate strip 20 and against the heated surface of the platen 35. Contact is maintained for a time sufficient to cause image-forming reaction in the image areas at the copy-sheet surface. The table 38 is then lowered, leaving the imaged copy-sheet lightly adhered to the surface of the intermediate.

The feed roll 23 is now caused to rotate in a reverse direction so as to withdraw the heated intermediate 20 past the guide roll 30, where the copy-sheet is stripped from the now depleted exposed area of the intermediate to be recovered on the recovery chute 51. The intermediate is returned to its original position, the exposed and depleted area again being positioned over the eX- posure chamber 26, the recovered portion of the strip being rewound on feed roll 21. The machine is then in readiness for insertion of the same or another original and a repetition of the copying sequence.

Rather than requiring re-insertion of an original for making additional copies thereof, the machine provides for retention of the original and modification of the copying procedure so that any desired number of copies may be made automatically. For this purpose the pressure platen 15 is provided with a porous face plate 52 and an orifice 53 connected to a reversing valve and thence to an air pump, not shown in FIGURE 2. The machine is also provided with an adjustable timer which is pre-set to the desired number of copies and with control means for modifying the intermediate rewind cycle as will be further described.

Initial insertion of the graphic original is made in the same manner as previously described. As the sequence continues, the interior of the pressure platen is placed under reduced pressure by evacuation to the air pump, so that as the exposure step is completed and the platen is lifted, the original is held by atmospheric pressure against the porous face plate 52. After the heat-printing step, the intermediate is returned to the exposure position for the purpose of releasing the copy to the chute 51 and is then reversed to bring the edge of the depleted area to the edge of the exposure panel 25, thereby leaving the panel covered with a next adjacent unexposed portion of the strip. The light-exposure and heat-print sequence is repeated in the manner described for the indicated number of times. At the final sequence, the position of the valve to the air pump is reversed so that air is forced into the pressure platen, thereby forcing the original from the porous plate and permitting it to pass with the exposed intermediate from the exposure area for recovery at the chute 50. In this final sequence the intermediate remains with the last exposed and depleted portion again returned to the exposure area.

A somewhat different sequence is necessary to permit copying from books or other originals which cannot be fed through the port 12. For book-copying the intermediate is first advanced to place an unexposed portion over the exposure area. The pressure platen 15 is tilted upwardly by means of the handle 16 to permit the desired portion of the book to be laid over the intermediate, With the page to be copied in contact therewith; the spine of the book lies along the juncture of the plate and the sloping front 55, the free cover and pages being supported on the ledge 56. The cover of the platen 15 is Wedge-shaped so that only the page of which a copy is desired need be placed on the intermediate, the remaining pages and cover then lying on the sloped forward surface of the cover. The pressure platen is returned to position and forced tightly against the enclosed portion of the book, the bottom page of which is then exposed through the intermediate to light from lamps 34. After releasing the pressure platen and removing the book, the remainder of the sequence is continued as previously described.

To renew the supply of copy-sheets, the handle 17 is retracted thereby permitting the supporting base 57, and the spring-mounted tray 18 and control bar 40, to descend. The stack of sheets is placed on the tray with the forward edge against the bar and with the treated surfaces upward, and the whole is then raised against the feed roll 39 by advancing the handle 17. Similar paper feed apparatus is described and claimed in application Ser. No. 301,340 filed Aug. 12, 1963, now Patent No. 3,260,521.

The operation of the machine is directed from the control panel 14, which includes an on-oif button 60, an exposure control knob 61, a book copier control button 62, and a combination of starter button 63 and copy counter knob 64. A window 65 gives a view of the counter dial indicating the number of copies to be made.

Some further details of components of a preferred commercial embodiment of the copying machine as hereinbefore described will now be given for purposes of further illustration, it being understood that the invention is not restricted thereto or limited thereby.

The short entry roll 28 employed to insert the printed sheet original 27 has an extremely soft covering of coarse polyurethane foam and applies a very light force to the original, which is thereby held with its leading edge in accurate registry at the nip of rolls 23 and 24 and in readiness to be advanced when the roll 23 is rotated. The force supplied is so light that very thin paper originals are not folded or wrinkled under the continuing rotation of the roll 28 but are merely held with the leading edge against the feed plate 19 in position as indicated. On the contrary, the feed roll 23 has a rigid body covered with a thin envelope of soft rubber and therefore having a high frictional force for paper while undergoing minimum change in circumference with changes in temperature. The pressure roll 24 is likewise rubber-covered and is held against roll 23 under spring tension.

The mechanism by which the cam 33 acts to depress the pressure platen 15 is schematically shown in greater detail in FIGURE 3. The cam 33 acts on a yoke 70' which is suspended from a frame on springs 71 and is in turn attached to a crossbar 72 by springs 73. Uprights 74 to which the crossbar is attached are held against the yoke under the spring tension. Arms 75 are pivotally attached at the upper ends of the uprights 74, being held at approximately a right angle therewith by braces 76 pivotally attached to uprights 74 at crossbar 72 and held at their other ends by catch members 77 which are pivotally attached to arms 75 at cross-member 78. A further cross-member 79 carries at its central point a ball joint member 80 which connects with a corresponding socket member centrally located on the upper surface of pressure platen 15. The handle 16, attached to a catch member 77, permits disengagement of the catch members so that the pressure platen and the supporting arms and cross-members may be pivoted upwardly when desired, as in positioning a book for copying. The tension afforded by spring 73 determines the pressure applied by the member 15 against the exposure panel 25 and is adjustable by adjustment of springs 73. The ball 80 and associated socket permits equalization of pressure over the entire compression area. The springs 71 maintain the assembly in open condition against the cam 33 when the latter is positioned as shown.

The pressure platen 15 has a reinforced rigid back 81 and a porous face 52, and is totally enclosed so that the interior may be placed at above or below atmospheric pressure. The face plate conveniently consists of a perforated rigid metal plate covered with a resilient pad of porous polyurethane foam which in turn is covered with a tightly woven porous cotton fabric.

The exposure chamber 26 comprises a box-like chamber 47 having a diffusely reflective interior surface and containing a number of incandescent filament lamps 34. Typically, a chamber capable of exposing an 8 /2 x 14 inch original will contain thirty-two 40-watt bulbs. The considerable heat generated is removed by means of forced air entering the chamber through openings 82 in the side walls and exhausting through openings 83 in the bottom to appropriate ducts, not shown.

Uniformity of exposure and high contrast between image and background are improved by the use of a semi-reflective coating applied to the outer surface of the glass plate 25. A thin coating of titanium dioxide pigmented polystyrene resin is useful for this purpose. A commercially available coating known as Hi Efliciency Coating 701 in an amount permitting transmission of 30% of normal incident light of 5400 A. wavelength is particularly effective.

A curved aluminum plate 66 serves as the base of the heater platen 35. The plate is covered on the convex surface with a silicone rubber blanket 67 containing resistance elements 68 embedded therein and covered with another curved aluminum plate 69 to impart added rigidity. A thermistor 48 serves as a temperature sensing element for temperature control means, not shown, by which the current flow to the heater elements 68 is controlled. A thin cotton fabric, not shown, is preferably suspended across the face or concave surface of the plate 66 to provide improved uniformity of heating.

Pressure table 38 likewise is formed on a curved heavy aluminum plate base 58, the curvature conforming to that of the platen 35. The metal plate is covered with a layer of resilient polyurethane sponge 59 and with a further layer of thin cotton fabric. 7

Supply roll 21 is dynamically biased in the windup direction, i.e., counterclockwise as viewed in FIGURE 2, through a slipping clutch 81 which permits the strip 20 to be unwound from the roll under moderate tension but rewinds the material on the roll when the tension is sufficiently reduced. Similarly, windup roll 32 is biased in the windup direction, also counterclockwise as viewed in FIGURE 2, by a slipping clutch 82. On the contrary, feed roll 23 is accurately and positively driven in either direction as required, the tension supplied thereby to the strip 20 being sufficient to over-ride either of clutches 81 and 82. a

At the copy-paper feed station, feed roll 39 is driven through an over-ride clutch 83. The topmost copysheet from stack 37 is thereby forced past the spring mounted control bar 40 and along the curved surface of the guide panel 41 against the lightly spring-biased fingers 42 and into the nip between rolls 43 and 44. The sheet is ad vanced into position on the pressure table 38, the override clutch 83 permitting free forward rotation of the feed roll 39 as the sheet is drawn forward by the rolls 43, 44.

The curved fingers 42 and their tensioning springs are pivoted about a supporting shaft 84 to which the frame 85 supporting the short pressure roll 44 is rigidly mounted. The shaft 84 is held under torsion to bias the pressure roll 44 toward the feed roll 43. The fingers 42, in alignment with the deep circumferential grooves 86 in the periphery of the roll 43, ride on the upper surface of the copy-sheet as the latter is drawn between the rolls 43 and 44. As the trailing edge of the sheet passes the nip between the rolls, it is held against the surface of roll 43 by the tips of the pressure fingers 42 to a point just short of theforwardmost position of the roll face, thus providing accurate placement of the sheet in position for copying. If desired, some braking action may be applied to the copy-sheet as it is pushed into position by rolls 43 and 44 so that the trailing edge will remain indexed against the roll surface. One convenient method is to adjust the rest position of the pressure table 38 so that the copy sheet is forced to drag lightly against the surface of the exposed intermediate sheet 20 as the copy-sheet advances.

It is to be understood that suitable circuit components and auxiliary equipment are provided so as to accomplish the various operations and sequences as described. For example a step switch is used, together with suitable relays, to carry out the entire repetitive copying sequence for making any desired number of copies of a single original. Due to the considerable power required it is found desirable to disconnect the heater elements 68 during the exposure cycle, i.e., while the lamps 34 are actuated.

What is claimed is as follows:

1. A copying machine comprising, in combination: exposure means for reflex exposure of a light-sensitive intermediate sheet material and an original, including a light source, a transparent supporting surface, and a retractable pressure-cover; heating means for heating the exposed intermediate in contact with a copy sheet, including a heat source having a smooth contact surface and a retractable pressure-pad; advancing and retracting means for moving an elongate strip of said lightsensitive intermediate sheet material to place a section thereof tautly into position for said reflex exposure, thence into position for said heating, and thence back to the exposure position; first feed means for placing a graphic original beneath said pressure-cover and in smooth pressure-contact with a said section of said intermediate sheet supported on said transparent supporting surface in position for reflex exposure; second feed means for placing a copy-sheet upon said pressure-pad and in smooth pressure-contact with said section of said intermediate sheet disposed beneath said contact surface in position for heating; and control means for causing advancing and retracting of said pressure-cover, advancing and retracting of said pressure-pad, and advancing and retracting of said strip of intermediate sheet material in copying sequence for producing on said copysheet a copy of said graphic original.

2. A copying machine comprising, in combination: a light-box having a transparent cover for smoothly supporting a section of light-sensitive sheet material and original in position for reflex exposure; a pressure-cover for smoothly pressing said section of sheet material and said original against said light-box cover; a heating platen for heating the exposed section of light-sensitive sheet material in contact with a copy-sheet; a pressure-pad conformable with said platen for smoothly pressing said section of sheet material and said copy-sheet thereagainst; means for supporting a supply roll and a windup roll of said intermediate sheet material with a connecting length of said sheet material passing across said light box and across said heating platen; advancing and retracting means for moving said intermediate sheet material tautly between said supply roll and said windup roll in either direction so as to place a section of said material into position for said exposure, thence into position for said heating, and thence back to the exposure position; means for holding said pressure-cover in closed position against a said graphic original and a said section of said intermediate supported on said transparent cover during lightexposure and for then retracting said pressure-cover; means for holding said pressure-pad in closed position against a said copy-sheet and said section of said intermediate in contact with said heating platen during heat processing thereof, and for then retracting said pressurepad; and means for separating said copy-sheet from said intermediate during retraction of said section of said intermediate in the direction of said supply roll.

3. A copying machine comprising, in combination: a light-box having a transparent cover for smoothly supporting sheet materials to be irradiated; a pressure-cover for smoothly pressing sheet materials against said transparent cove-r, said pressurecover having a porous pressure-face, and means for controlling air pressure against the inner surface thereof; a heating platen for heating a section of sheet material after irradiation of said section at said light box; a pressure-pad conformable with said platen; means for drawing an elongate strip of light-sensitive intermediate sheet material tautly and in either direction across said light-box and said platen wherewith to place a section of said strip first into position for irradiation at said light-box, thence into position for heating at said platen, and thence back to the irradiation position; first feed means for inserting a graphic original in sheet form beneath said pressure-cover and in congruency with a section of said intermediate against said transparent cover; means for holding said pressure-cover in closed position against said original and said section on said transparent cover during light-exposure and for then retracting said pressure-cover; means for separating said original and said section while advancing said section into congruency with said heating platen; second feed means for inserting a copy-sheet into congruency with said section and adjacent said pressure-pad; means for holding said pressure-pad in closed position against said copy-sheet and said section in contact with said heating platen during heat processing thereof, and for then retracting said pressure-pad; and means for separating said copy-sheet from said intermediate during retraction of said section in the direction of said light-box.

4. The copying machine of claim 3 wherein the first feed means comprises a smooth sheet-supporting panel and a short soft sponge roller in light surface contact therewith, and means for rotating said roller in a direction to cause a thin sheet of paper supported on said panel to be fed into said machine, the frictional contact between said roller and said paper being insufiicient to cause crumpling of said paper when the leading edge is prevented from advancing.

5. The copying machine of claim 3 wherein the second feed means comprises a doubly circumferentially grooved feed roll, pressure fingers aligned with and biased toward the grooves in said feed roll, and a pressure roll parallel with and biased toward said feed roll in the same direction as said fingers and lying between said grooves.

6. A copying machine comprising, in combination: a main frame, a light-box attached to said frame, having a transparent cover for smoothly supporting sheet materials to be irradiated by reflex exposure; a pressure-cover for smoothly pressing sheet materials against said transparent cover, said pressure-cover having a flat lower pressuresurface, a wedge-shaped forward edge portion, and being flexibly suspended from a supporting force-applying framework hinged adjacent the rearward portion of said pressure-cover to permit tilting of said pressure-cover to a position wherein said wedge-shaped forward edge portion is away from said transparent cover, said framework including releasable locking means for restraining said pressure-cover from said tilting, said framework being suspended from said frame and being capable of b ing lowered to place said pressure-cover in pressure contact with said light-box and of being raised to retract said pressure-cover therefrom; a heating platen attached to said frame; a pressure-pad conformable with said platen and suspended from said frame; means for drawing an elongate strip of light-sensitive intermediate sheet material tautly and in either direction across said light-box and said platen wherewith first to place a section of said strip into position for irradiation between said light-box and said pressure-cover, thence to advance said section into position for heating between said platen and said pressurepad, and thence to return said section to the irradiation position; means for lowering and raising said framework; means for placing a copy-sheet upon said pressure-pad and in smooth pressure-contact with a freshly reflex exposed section of said intermediate sheet disposed beneath said heating platen and in position for heating; and means for separating said copy-sheet from said intermediate sheet section while retracting said section toward said light-box.

7. The copying machine of claim 1 wherein said first feed means comprises a temporary stop means, a support having a smooth surface directed toward said stop means, and a short feed roller having a soft highly compressible polyurethane foam surface under light compression toward said support surface and continuously rotatable in a direction to urge a sheet of paper placed between said support surface and said roller toward said stop means.

8. The copying machine of claim 1 wherein said second feed means comprises a doubly circumferentially grooved paper feed roll, a pressure roll pressing against said feed rool between the circumferential grooves, and curved pressure fingers fitting into and lightly biased toward said grooves, the tips of said fingers extending past the nip position of the rolls and approximately to the forwardmost position of the face of said feed roll whereby a sheet of said feed means, and against slight forces applied to said sheet, is placed precise dynamic paper fed through braking or dragging and maintained with its trailing edge in registry with said tips.

9. A copying machine, adapted for making copies of printed originals by a process involving reflex exposure of an original and a section of an elongate strip of lightsensitive intermediate sheet material, followed by a heatprinting step involving heating of the reflex-exposed section in contact with a copy-sheet with which the less exposed section in contact with a copy-sheet with which the less exposed portions of the intermediate sheet remain visibly inter-reactive, said copying machine comprising: an exposure station including exposure means for subjecting said original and said section of the intermediate to reflex exposure; means for removing said original from the exposed section of the intermediate; a heat-printing station including means for introducing a said copy-sheet and heat-printing means for heating the exposed section in contact with said copy-sheet; and advancing and retracting means for advancing said strip and said original to place an unexposed section at said exposure station in position for reflex exposure, thence advancing said strip to place the reflex-exposed section in superposition with said copy-sheet for heat-printing at said heat-printing station, and thence retracting said strip to discharge said copy-sheet and to return said exposed section to the exposure position.

References Cited by the Examiner UNITED STATES PATENTS 2,600,580 6/1952 Sabel et a1. 95-73 X 2,917,985 12/1959 Williamson 95-75 3,085,488 4/1963 Heiart 95-77.5 X 3,093,039 6/1963 Rheinfrank 95l.7

JULIA E. COINER, Primary Examiner. 

1. A COPYING MACHINE COMPRISING, IN COMBINATION: EXPOSURE MEANS FOR REFLEX EXPOSURE OF A LIGHT-SENSITIVE INTERMEDIATE SHEET MATERIAL AND AN ORIGINAL, INCLUDING A LIGHT SOURCE, A TRANSPARENT SUPPORTING SURFACE, AND A RETRACTABLE PRESSURE-COVER; HEATING MEANS FOR HEATING THE EXPOSED INTERMEDIATE IN CONTACT WITH A COPY SHEET, INCLUDING A HEAT SOURCE HAVING A SMOOTH CONTACT SURFACE AND A RETRACTABLE PRESSURE-PAD; ADVANCING AND RETRACTING MEANS FOR MOVING AN ELONGATE STRIP OF SAID LIGHTSENSITIVE INTERMEDIATE SHEET MATERIAL TO PLACE A SECTION THEREOF TAUTLY INTO POSITION FOR SAID REFLEX EXPOSURE, THENCE INTO POSITION FOR SAID HEATING, AND THENCE BACK TO THE EXPOSURE POSITION; FIRST FEED MEANS FOR PLACING A GRAPHIC ORIGINAL BENEATH SAID PRESSURE-COVER AND IN SMOOTH PRESSURE-CONTACT WITH A SAID SECTION OF SAID INTERMEDIATE SHEET SUPPORTED ON SAID TRANSPARENT SUPPORTING SURFACE IN POSITION FOR REFLEX EXPOSURE; SECOND FEED MEANS FOR PLACING A COPY-SHEET UPON SAID PRESSURE-PAD AND IN SMOOTH PRESSURE-CONTACT WITH SAID SECTION OF SAID INTERMEDIATE SHEET DISPOSED BENEATH SAID CONTACT SURFACE IN POSITION FOR HEATING; AND CONTROL MEANS FOR CAUSING ADVANCING AND RETRACTING OF SAID PRESSURE-COVER, ADVANCING AND RETRACTING OF SAID PRESSURE-PAD, AND ADVANCING AND RETRACTING OF SAID STRIP OF INTERMEDIATE SHEET MATERIAL IN COPYING SEQUENCE FOR PRODUCING ON SAID COPYSHEET A COPY OF SAID GRAPHIC ORIGINAL. 